Patients that have respiratory difficulties often must be placed on a mechanical ventilator. These difficulties may be pathological in nature or may be due to the fact that a patient is too weak or sedated to independently proper respiration functions. Often, the patient may be spontaneously attempting to breathe but not able to complete a full respiratory cycle. In these cases mechanically assisted ventilation is provided. In mechanically assisted ventilation a combination and pressure and/or flow sensors detect a patient's breath attempt. This detection triggers the delivery of a mechanical breath. This breath is provided by the delivery of a pulse or plug of medical gases under a pressure that is sufficient to overcome the resistance of the patient's airway to fill the lungs. When this pulse of medical gas is discontinued the natural compliance of the patient's chest wall forces the delivered breath out of the patient in an expiratory phase.
Mechanical ventilation can comprise the delivery of air, but often the breath that is delivered is formed of a mixture of various medical gasses. These gasses may include oxygen, helium, nitric oxide (NO), a drug aerosol, or, in the case of anesthesia delivery, an anesthetic agent. The proper combination of medical gasses would be decided upon by the clinician in response to the ailments of the patient.
Efficient mechanical ventilation requires a quality ventilator-patient interface. This requires a quality seal around the patient airway thereby providing efficient delivery of the medical gasses. There are many varieties of ventilator-patient interfaces. These varieties include face masks which cover the patient's mouth and nose, an endotracheal tube, or a nasal cannula. While there are advantages to each of the patient interfaces a nasal cannula presents the advantage of providing a higher quality connection to the patient's respiratory system than a face mask while being less invasive than an endotracheal tube.
In the delivery of some medical gasses to a patient it is desirable to keep the gasses separate until shortly before they are delivered to the patient. This may arise due to properties desired in each of the gasses, structural components of the mechanical ventilator, or because of adverse reactions between different medical gasses. One example of such adverse reactions is the reaction that takes place when oxygen is mixed with nitric oxide. Nitric oxide is a gas that, when inhaled, acts to dilate blood vessels in the lungs, improving oxygenation of the blood and reducing pulmonary hypertension. Therefore it is often desired to deliver a combination of nitric oxide to improve lung function with an increased concentration of oxygen to improve oxygen transfer. However, oxygen and nitric oxide react to form nitrogen dioxide (NO2), a toxic substance. Therefore, to reduce the production of nitric oxide it is desirable to keep the supply of oxygen and nitric oxide separate until just before it is delivered to the patient.
In many clinical or critical care situations a patient is connected to a wide variety of monitoring and/or support devices. These devices may include patient monitoring such as ECG, EMG, or EEG, fluid and/or nutritional support in the form of a catheter, patient waste removal, or respiratory support in the form of a mechanical ventilator. A challenge arises with this multitude of patient connections in keeping them tangle free and properly connected to the patient. This becomes difficult when the patient is moving, clinicians are moving about the patient, or the patient (and connected equipment) must be moved within the treatment facility. While data connections are more susceptible to disconnection from the patient gasses or fluid delivery connections are susceptible to kinks or entanglements in the lines resulting in restricted or interrupted delivery to the patient.
Therefore it is desirable in the field of mechanical ventilation to provide a kink resistant nasal cannula that can separately deliver multiple medical gasses to a location proximal to a patient.